Samples over 12 months were collected from four tanks and effluent (September 2000-August 2001) along the station.  The increase in number of total phytoplankton standing crop, the high concentrations of nutrients and low species diversity are the characteristics of eutrophicated habitats. The total phytoplankton standing crop ranged from   914.6 individuals x 10⁴/L at primary sedimentation tank to 6442.3 individuals x 10⁴/L at aeration tank. The phytoplankton community was represented by a total of 61 species belonging to 36 genera and 7 classes in the investigated station, namely Chlorophyceae, Bacillariophyceae, Cyanophyceae, Euglenophyceae, Dinophyceae, Xanthophyceae and Cryptophyceae.  Approximately all the species of the last four groups and Bacillariophyceae were tolerant species and considered as eutrophic indicators.